Self-aligning hollow-sphere bearing piston



CLD

Patented Jan. 6, 1931i Y' i stares rarlf' GFF insana WILLIAM J. 1.MOORE, ornnwvong N.

snLnALIGNINe- HOLLOW-ernaar; Bnl/animerk rrs'ron np'piicanon iearebrury21, 1929; serial No. 341,722.

My invention relates v to new and useful improvements in pistonsyforengines or'ino'- tors of various kinds,r especially internal.

combustion engines. n y i Itrelates more particularly to that class ofpist-ons in which the piston rodis connected to the `piston vby meansfofa hollow sphere or ball insteadof by means of the usual cylindricalpiston pins working in bosses cast at opposite points on thepistonfwall,r the kspherical or ball bearing, having Vnumerous points ofsuperiority over .the other common forni' of cylindrical vbosses orconnection@ My improved self-aligning hollow sphere bearing piston hasmany improvements the construction and design of engine pistons. rEheseimproved details `are intendedv to overcome defects in the present' formof engine n ing means. Another and greater defect of the cylindrical.pins and bosses is that no matter how .true and accurately theipistonWalls may be machined .or how carefully finished, the moment thepistonis heated or putinto working operation, it distorts out of rounddue to theconcentrated heavy bosses kand the unequal working strainscarried by the'thi'n side walls, so that all the benefitsV ofcarefulmachining and accuracy of flnishare lost.

i still further and more vserious. defect is if .that no matter, howcarefully the pin is aligned in relation to the side walls of the pistonand the cylinder walls, any springing or misalignment of the crank shaftpin or crank shaft bearings produces excessive a1i kstrains in thepiston pin bearingsand dis-l tortion in the thin sidewalls of thepiston, and causes piston side slap, asmwell yas unequal wear and strainin the piston pin and nection therewith. Y. Figure 2 is asi or springmorey orfless; so that theforegoing conditions always exist in enginepistons having cylindrical piston pins. VThe perfect alignment neededfor the parts is further seriouslyv aifected by the misaligmnentanddisltortion of the main engine and cylinder castings; These defects` areeiiec'tuallyfand coinpletely overcome by my improvedself-aligning'hollow sphere bearingpiston, asl shall `hereinafter pointout.v

' My inventionmay thereforerbe saidto corn sist essentiallyintheconstruction7 combina-v tion and arrangement of parts, substanti ally as will be hereinafter described and claimed.

ln the accompanying drawing illustrating my invention: g i 'i l i'Figure 1 is a vertical sectionof inyviniproved hollow sphere .bearingpiston coinpletely assembled andthe pistony rod in con` piston shellalone, lwith its head removed', and Yomitting the hollow sphere andother removable parts. v o i A .A

Figure Sis a top plan view of the piston and piston head.

Figure 4 isa top plan View with the head removed to showthe interiorconstruction. `Figure 5 is a detail sectional view of the hollow 'spherebearing member carried on the,

end ofthe piston connecting rod. y l Y Figure 6 is an inverted detailbott-om plan View of the screw head of the piston. y

Figure 7 Vis a cross-sectional detail view of,

they semi-sphericalbearing cap that rests 4'on top of the hollowsphere,`and against which the piston head is screwed down.l

VLike characters of reference denotelike parts throughout all thedifferent figures of the drawing;

The body of the piston is a hollow cylinder of any desired length' anddiameter, perma! nently open at one end, lwhile the other endV isclo'sedby a kremovable screwed .in head. The Walls `are of uniform thicknesstransversely from the'top to the bottom, and have no concentrated orunequally thick bosses to prov-.ide cylindrical .pin bearings. and areman della Sea-isn of nali` tra piston pin bosses. 'All crank shaftsunderall normal working lconditionswill distort therefore not subject toshrinkage strains in 100 l Y V`With`thisg construction ofpiston'bodyall'Y Y one pointin the thinvside Wall; and there',-vv

casting. Y The end portion l which receives i the removable head 5 isnecessarily thicker than `the rest ofthe Wall on account of the pistonring and is internally-screwthreaded at 4, While the outside of thisportion carries one or more piston rings 3. The Wall of this body fromthe thickest section l to the other end of skirt 2 is of a reducedthickness,.grad` ually tapering tothe end. 'i The piston body in allnormal sizes used in automobile or airsizes around three inches indiameter, so commonly used, the appearanceof the pressed piston body andthe Vproblems involved in making the saine are veryV much those ofthefamous ,75 shells used in Warfare.

load strains are continuously and uniformly carried by the l'cylindricalside Wallthrough'f out their, entirecircumference and: canrproduce noVunequal strain or distortion at 'any fore vthefpiston Walls once theyare machined and inish'ed'true and roundremain so and 1 are notunequally distorted Yor strained un;` der any normal Workingconditions.. The' skirtfofthe piston Wall, as 2, isA continuousthrnughout'its entire lengthv and'cirruimten` ence, thus giving amaximum of wearingand bearing surface, and" the self aligning insuresuniformity throughout thev entire area. l

The sidewall or skirt 2 can be made very light belovvv thepistonringarea, as it is not subjectto undue 'shrinkage strains or unequal 1 loadstrains, and having continuous surfaceof eXtra large area, extrathickness isnot i required for carrying away thev heat, but' Y orgrinding processes and-.ofthe quickest and cheapest kind, and no. cross`boring` is suiicientv strength .so that ythey Will not "4b crush underWorking conditions.v Further,

owing tothe cylindrical form offtheskirt and the fact that thesesidewalls are only subject tocompression/or crushing strains, beloyy'thepiston'ringarea they may 'bemade of a tapering thickness andapproaching` egg` shell1 `thinnes s at the bottom lofthe/pistonanditherefore of theV lightest possible con-v struction.

` The pistonbody and its headmaybemade of ancas't or; forged metal, andkfinished all over, in ordelitglnsure absolute unifornntyv in yvgeight,all operations` bein@ simpleD lathe required. Theconstruction can bemadeas a cast metal, either in cast iron orrcast aluminumyoraiorged orpressed inetalin steel or y duraluniin f'b'ut, preferablyV ofv aluminumAl allo fonA account/fof, the` reat savino' in Weigh@ as with highvengine speeds the Weight 'of the.. reciprocatingparts practicallydeterminesthe.maximum enginecan'berun.

Inside of ,the body;2' is an :integral cylindrie-a1;-

Paeially Spheres, bearing. wall oi'. bearing pressure speed at whichthe.

Gand piston Wall 2 and 'is provided With a f series of oil holes 8. Theother end of mem# ber'6 is open at 28 to allow the loose entry oiconnectingrod `16, said end of member 6 jhaving an internal rpartlyspherical surface Plane @Heines iS verre/@Saly pressed, ander 15.9:supportthe lower-portion of the hollow sphere 14 carried on the end ofconnecting 1 rodil6.r 'Insideof inner. cylinder 6 the semigage'thethreads 4 in the end of the piston shell l, so thiltrhrcad 5 may screwfirmly into the piston, andminvay hold firmly down on cap Vl() 'andAsphere ll.' Due tol the line threads of the piston head'itgcanbeadjusted to a nicety,"the samefas the,` capon the end or theconnecting rod. Yl/Vlien thel head 5 is properly adjusted itis locked inplace by two hollow Vset screWsiQS, having hexagonal Wrench holes 2:therein. These screws 23 screivinto threadedopenings 26 inthe edge orthe head 5 near thaf threads 4. The set screws 23are attened on oneside, at 25, and When slightly turnedtheir threads Will bite into thelthreadtf onthle'piston body andA se- Y curely lock headn5l inpositionyalso when released the4 hollow openings 24l of the set screvvshold the Wrench usedY in, demountiiig Y Lings 2O,v that bear doym on thecap l0 to hold theila'ttergin place'- I The separat-e andremovablenpistonY head has many advantages in` itself, besides providingfor ytop accessibility to al-l'inner piston parts, Yand especially'inthat it produces less distortion in the piston head -due to the unequalheating' at different points of the piston head.

TheA central partvof a, piston head must alwaysbehotter andl eXpand toay greater degreev thanlftheside Walls nearer the jacket, and When themainv piston body and the piston head arercast, as a .unity the, greatereX- pansion near thecenter of the head communicates to the eXtreme edgesof; the piston body, causinganunduedistortion of the entire head end Vofvthe piston. To counteract this it` is common practice to` recess thetop end ofthe,V- side Wall above theftop piston ring; and also` to makethe entire piston head unduly thick'toprovide for a Vgreater masser.Avolumeof metal to assist in carrying off the excessive heat vofthecentral portion of thelpistonhead.` i

llt)

ifa

the threads to carry off all heat as efficiently p as with a solidintegral head piston; The top edge of the-piston body `part 1 isprovided with two small drilled' holes 7,27',

on opposite sides for inserting -a-,wrench-or spanner for holding thepistonbodydmase sembling and demountingv ,the complete pisa ton; andthis isdone tohold the fpistonbody: firmly while` another wrench-z isoperating, with the hollow set screws23v tdreleaseyorfasten the pistonhead 5k in-Vpla ce.- k Thus itk willjbe seen how aremovablekpiston'fhead enables the complete piston unit tor be fassent bled ordisassembled from-the topk side, and it is never necessary to approachanypartof the pieten or its assembly from the-,bottom lside of` theengine. By .merely removing the cylinder head any yadjustments;can-bemade in case ofneces'sity, andfin fact 4.the en, tire pistonbody,piston`rings, hollow sphereA and other parts may becompletely.removed from the top side;l forafter `removingthe pistonA head and theupper; semi-spherical;

. bearing cap,.thefpistonbodyg'can ,bewdroppedY down to givefaccesstothe hollow sphereorg balland the connectingrod. The piston body sidewall or skirt2 isplQ'f: vided with a series 'of truncated conical ortaper holes 9, having the larger diameter at the ,outside surface ofside wall 2 and against the enclosing cylinder wall. These holes producea series ofsmall pockets for collecting the oil splashed into the insideo-f the piston. By a proper arrangement this supplies a continuous filmof oil over the entire' area of the surface of the piston and cylinderwalls; and it is a well known fact that such a continuous film of oil ispractically acure for piston side slap. c

The semi-spherical bearing cap which fits down into the cylindicalinner` yintegral piston member 6, to hold the hollow sphere 14 fromabove, is preferably of hard cast iron or steel. It has a recessed top11. See Figure 7'. This recess 11 permits the accumulation of the oilsplashed and thrown through the many inclined holes in the diaphragmannulus between the piston skirt 2 and inner member 6, or these holes 8are'at the point whereV the piston body wall joins the lower bearing cupfor the hollow sphere 14. These yholes 8 cause a continuous supply ofoil to be splashed to the recessed top 11 of the bearing cap 10,

and which through the holes 12 and 13 in the cap10fthisjcapa10distributes the oil to the Yupperand;alsofto the; lower half ofthehollow ali/spass now to a brief study ofthe feature y i which maybeassumed to be perhaps the most important element 1in kthe combinationofele mentsfmaking up r invention, namely, the hrol'lowf-sphere'or ball 14which is'carried on theend'of the-pistonconnectingprod 16 toconstitute a"lose: pivotal oruniversal ball joint connection between the connectingrod 16 and the spherical parts in' piston 14. This element is usuallyand preferably a hollow sphere', as shown,.lwhich1is truncated or slicedoff to permititherodr16-to enterit, said rod having aeshoulderagainstwhich the sph-ere 14 vis screwed on tightf I't will be noticed howeverthatthe element r14 maybe a .solid ball', `or may consist :ofinterconnected parts, or may have only apart'ial spherical curvaturewhich will correspond-to one for more spherical pieces The hollow'sphere .14, when of this .pre-i ferred form and structure, `forming aselfc aligning spherical bearing, is 'very light, and

asthe spherical surface. is subject only to compressionvof crushingstrains it can alsobe madeivery thin, and it'hasmany advantages over thecylindrical piston pin, besides the very/important .advantage of,self-aligning. i .The-hollow'sphere 14 has an innercylindricalaiosleev'e `like center 15, whichhas an internal screw thread21, whereby thesleeve L15-screws: on lthe thread 17i of rodA 16 downagainst theshoulder on rod 16. VThe sphere 14 iis-.-tlie,refoi."evsubstantially hollow, and Al term ita hollow sphere. It has .onopposite` side .holes 18,"V in which' are hollow. setscrews 119. thatengage Athefthreads 17 of rod 16.v Hence Ytheshollow sphereis screwed onthe upper vendfof the connecting rod 16 against agshoulder thereon, andis locked in position by thetwo hollowset screws. The main loadofff'thedownstroke is taken directly on the connectingrrod"shoulder, and.it is yonly on theuplstroke or lighter load that the straincomeszonfthethreads.- y l 1 f u Thehollowfsphere'bearing perfectlycompensates `v`forl any.v misalignment of cylinder walls, main enginecasting, crank shaft and crankfpimor .the springing of; the crank shaftunderload,1orfanyinisalignment due to bad workmanship,- and it`completely overcomes pistonl side slap. Its perfect `operation -isnot'vaifected by'bad manufacture, for should y,

the'center -of-thehollow'sphere not be concentricwith theycente'r'of thepiston body, itv

would lautomatically adjust itself to this error, as well as to errorsor misplacements ofotherjpartspfp,

The hollow sphere 14 `provides a much greater wearing surface than ispossible with a cylindricalpiston pin, .so thatthe load per stiuare,inchlis` therefore decreased, Aand the lifefo' thev .wearingelements is greatly `i11- 4 y imma:

creased; f Theincrease in much greater than seemspossibles from` casualconsideration. The Wearing :surhee's are[constantV and are 'alwaysi in1' Contact throughout their entire-rama. Int-operation they tend .toVwear"` in" and acquire 'hmdfan mirror like surfaces, andi theywilli-weerzien an almostindeinite timewith'out adgiustment AMany'changes in the details may-1 bei made withotexceeding' the scolnaof.theIclaims;

especially'Y variations .Y in: :the form; crelaton; and character of theparts.` Y WVhatI cla1m,is: f

1. A pistonoonsistingfessentiallyfiniai-hol;

low cylinder having ani integral innerconeen tric cylinder wall; formedwithagapartlysp'xer:

ical lower end, aaremovablelreadim one'endi of; ,the cylinder; Vvasemifspherica' .bearingieap' beneath said head, a: piston rodgmd'afspherical membery carried: thereon-,".wliiclaiisz supe ported between. the ysemi-spherinalxcapi; and

the lower partly sphericalV cylindrial member ofz-the1pi'ston-/ Y l A 2;In a piston .ofthewelasszy descrbedze combination of a hollow:cylnderhewinggan integral innen. eoncentriey sl'eeve-,hkeaY:wall:V

whose connection: Lwith Y the Acylinder iseaa da phragm annulusprovided. wthdnbriean openings',VV andiwhose: inner: lower bearingjpnv.

tionis curved to correspond tothefjshapefof they piston rodi sphere,.a-removable"` serewthreaded head .in one-eindi oiifsaidf'c'flinder,van

inner-Y upper;spheriealicapafon theipist'onrrod sphere?Vhaving;lubrieantzopenings; and: 'aehol n low spherelwithin thenpperandilower spli'em's cal` bearing surfaces; together:with-fmiredyto. which thehollowspherelisfseeuredn i 1 3i In a. pistono thefclassi`desenibedilie. combination of a:hollowfeylinderfhaving an integraliopen+endedv inner* concentrif endl; il

the Connection; between .themhavin lja-fsexziefl of lubricant.'passages,A .andtthe-iiisi provide alowerrbearing foi-.fthespheci'oalej'oin member, an uppery independent:'sphermap for saidymember; said: capiibeingiperfonated the spherical jointmemberf'imovfalleewihin.I

. the said upper andi lowerfsphericalvservdes,

and a. piston rodwhichris :threadedtofengagesaid sphericalfjointmember;

. i. A piston Comprisingessentially-emu@ cylinder having. an integral:inner f'eoncentric' sleeve curved within. to providefitheflower` innerwall being curved near 'the buttomi tlfxfedsrofthefheadztolock the headin place,

anililnnerf'lowerjl partly spherical Vbearing integraI-ly'unitedWithithe body',r an inner upper removal)lef.partly4 spherical bearingarranged oppositestolthe lower-'bearing andh'eld in plfaee'- bylthehead, and afball orf sphere movabi@ Ybetivveiex'if thetwo:.beerngfmembers SilApit-'on comprising essentiallya hollow cylinder;a removable head inon'e end' thereof, apartlyspherie al? support'`iirrth'e cylinder and integral therewith; a removablesemi-sphericalbearingcapbeneath an'dheld inf place bysaidlvheadcombination with a hollow spiietiiealffmembermoyably carriedin said-` partly spherical 'support and beneath said semisphericalfbearing "cap, and af piston rod onnwhiehi the hollow spherical `memberis mountedl Y Y In testimony whereof Ifhereunto aiiix my signa-three" vWILLI-AMJ. P. MOORE.

^ endfof thefcylinder; aniupper curvedimemben withinl the upperV part of:the 1innerfnslefwfefillern provideA the top: ofthisvsocke't;Aai'splier-iowbl member insaid curvedsoeketgandfasrod carry;

ing said spherical member: y A 5. A piston comprising essentiaflllya;THow cylinder, avremovable headscrewedfintefne Y said head being taperingand-1 provided' with.T1

